Visually evoked responses in the primary cortex of rats are permanently changed by early postnatal treatment with monosodium-L-glutamate.
13 rats of the Long-Evans strain were treated from the first to the eleventh postnatal day (pd) with daily subcutaneous injections of 4 mg/g body weight monosodium-L-glutamate (MSG) in aqua dest. Further 13 rats were used as controls and received isotonic NaCl-solution on the same days. When rats were four months old, epidural electrodes were implanted on the visual cortex to investigate averaged evoked potential by flash (VEP) and by click stimuli (AEP). All VEP components of MSG rats were changed in their amplitudes and peak times. Mainly the early components were strongly reduced and irregularly split. AEP in the visual cortex of MSG rats were also significantly changed. Photically evoked afterdischarges (AD) were not statistically altered. The evoked potential analysis revealed great interindividual heterogeneity and their topographical distribution was also strongly modified. The postmortem macroscopic inspection of the brains resulted in strong atrophy of the optic nerves and the chiasma. During two-month observations we observed no restoration of the evoked potentials to normal values.
Brankack
J
J
Paul Flechsig Institute for Brain Research, Department of Neurophysiology, Karl Marx University, Leipzig, GDR.
Klingberg
F
F
D000161:Acoustic Stimulation; D000818:Animals; D000831:Animals, Newborn; D004594:Electrophysiology; D005072:Evoked Potentials, Auditory / Q000187:drug effects / Q000502:physiology; D005074:Evoked Potentials, Visual / Q000187:drug effects* / Q000502:physiology; D009897:Optic Chiasm / Q000187:drug effects / Q000473:pathology; D009900:Optic Nerve / Q000187:drug effects / Q000473:pathology; D010775:Photic Stimulation; D051381:Rats; D012970:Sodium Glutamate / Q000633:toxicity*; D014793:Visual Cortex / Q000187:drug effects* / Q000473:pathology / Q000502:physiology
D012970:Sodium Glutamate